A construction machine, such as an excavator, may have a movable beam (boom) configured to dig or otherwise move earthen materials. The beam of the machine is generally formed as an elongated hollow tube using a number of rigid sidewall parts or plates assembled together. Reinforcing cross members known as baffles may be present inside the hollow tube beam. These reinforcing cross members are traditionally attached inside the beam by welding prior to the final assembly of the beam. Generally, the welding is performed manually. Because the reinforcing members may be located at hard to reach positions within the beam, the welding operation is difficult, time consuming, and costly. In addition, the location of the reinforcing members, may make it difficult to ensure the quality of the weld joint.
Because the reinforcing members are attached at high stress areas and intensive longitudinal and torsion loads are applied to the beam during use, these loads create high stresses that result in fatigue cracks at the weld joints. Furthermore, cracks initiated at the weld joint may propagate through the beam's sidewalls or plates, which may lead to premature beam failure.
Thus, in light of these and other shortcomings in the art, there is a need for improved beam structures.